Quick-sealing access covers



F. E. MONSLER QUICK-SEALING ACCESS COVERS June 10, 1958 Filed July 22, 1954 INVENTOR.

Frank 5 Mans/er BY 2 2:2 %m

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Unite States This invention may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to covers for sealing openings, and more particularly to such covers as can be quickly applied and released.

In the design of ducts, containers and other such enclosures, it frequently is desirable to provide scalable access or inlet openings, and one of the more common covers for such openings is formed by a plate secured about its perimeter With a plurality of fasteners,'such as threaded studs, or cam-lock fasteners. These covers, however, have the rather obvious disadvantage of requiring manipulation of a plurality of fasteners with the result that excessive time is expended in removal or replacement especially when a frozen state produced by careless painting necessitates the employment of a tool.

Other factors contributing to the difliculties arise from the fact that each cover is practically tailor-made, so that it is replaceable in only one position. Further, in installations on naval vessels, duct distortion caused by collision or gun firing binds the fasteners to the cover and complicates removal.

A principal object of this invention is to provide an access cover capable of being quickly removed and replaced without the need for tools and, more specifically, one that requires only a single manipulation by the operator.

Another object is to provide such an access cover for ducts or pipes which presents a smooth and uninterrupted bore surface to avoid interference with the fluid flow characteristics and internal cleaning operations.

A further object is to provide a lockable access door with supplemental locking means to prevent accidental release.

Other objects are to provide an access cover having a simple and inexpensive construction, and which can be stamped of sheet metal.

These and other objects will become apparent from the detailed description and the accompanying drawing.

The objects of the invention are accomplished by a cover assembly which generally comprises a cover member, a locking member adapted to be anchored to the wall containing the opening, and cam means operative between the members for clamping the cover to the wall.

In a specific embodiment, the cover is preferably panshaped and is recessed to the extent of aligning the base of the cover in contiguous relation with the duct wall. The cover perimeter is provided with a flanged recess to seat a gasket adapted to be compressed to a rim secured to the wall around the opening. The locking member functions as a strongback and extends across the cover member with end portions adapted to slide under and be retained by clips that can be formed integrally with the rim. Locking detents may be provided to prevent accidental separation of the strongback in the clasped position. The cover is clamped into sealing engagement with the rim by a cam pivoted on the strongback and manually operable to thrust the coveragainst the rim. The cam has an actuating lever, preferably reciprocable in a plane normal to the cover which also serves to support the strongback during the sliding engagement and disengagement with the clips. This clasping movement between the strongback and the clips can be effected without a corresponding movement of the cover by providing means for aligning the members to permit a horizontal and vertical freedom of motion.

In the drawing, Fig. 1 is a plan top view of an assembled cover, partially in section, constructed according to the invention and sealed over a wall opening; and Figs. 2 and 3 are sectional views taken along lines II-II and III-III, respectively, of Fig. 1.

Referring to the drawing, the cover assembly is generally designated by the reference numeral 10, and is shown sealed over an access opening 12 which may be provided in a wall 14 of an enclosure member, such as a container, cabinet, duct, or the like.

Cover assembly 10 includes a cover or cap member 16 adapted to be sealed to a clamping edge 18 integrally formed with wall 14, and a locking member or strongback 20 which functions as a backing support to enable the cover to be clamped in sealing position. The plan and cross-sectional configuration of cover 16 can be varied depending on the particular installation.

When cover 16 is circular, as illustrated, the clamping edge is rim-shaped and can be formed as an extension of wall 14, or as a separate member having a flanged portion 22 welded, riveted or-otherwise secured to the wall around the perimeter of opening 12. To enable the cover to be anchored to the wall, a plurality of clips 24 may be secured to rim 18 or wall 14, each clip cooperating with a corresponding depending lip 26 on strongback 20 to form a sliding clasp connection. As will be described, supplemental means are provided for locking the clips and the strongback in their clasped position. The edge of cover 16 has an annular groove'27 for seating a gasket 28 adapted to engage rim 18 and seal the opening when the cover is clamped in position.

When the cover assembly is associated with a duct or pipe designed for fluid transmission, minimum resistance to the flow is achieved by forming cover 16 into a panshape adapted to fit snugly within rim 18, the cover being recessed to a depth to align bottom wall 29 with wall 14 and form a smooth and uninterrupted bore surface. The absence of any inwardly projecting cover structure simplifies duct cleaning operations and avoids interference with dampers or vane turns that may be present.

Cover 16 is clamped to rim 18 by a force applied between strongback 20 and the cover, and in the preferred embodiment this is accomplished by a cam unit 30 that may be mounted on one of these members and operable against the other. Cam unit 30 which, along with the other component parts, may be stamped of sheet metal, comprises a pair of spaced cams 32 each pivotably movable in a plane normal to the cover on a pin 34 extending through the sides of channel-shaped strongback 20. Cams 32, in turn, are actuated by an integral lever arm 36 terminating in a handle portion 38 that also functions to provide a convenient means for moving the strongback in and out of engagement with clips 24. Each cam 32 has a high point 40 which when rotated into clamping position (Fig. 2) bears against cover 16 and forces gasket 28 into sealed engagement with rim 18. As may be noted, cam high points 40 in the clamping position have been rotated beyond their dead center position and are retained in their clamping position by the resiliency of cover 16 and such a condition persists until lever 36 is intentionally lifted by the operator to the broken line position in Fig. 2 which releases the cams by moving the high points to the other side of pin 34. A bearing plate 42 may be mounted on the cover to prevent damage by the scraping action of the cams.

Cam unit 30 provides a simple and positive acting means for clamping the cover to the duct Wall through engagement of strongback lips 26 and clips 24. Nevertheless, some possibility exists that the strongback may be rotated by shock or concussion and be released from the clips. To avoid such occurrence and to insure proper alignment of the strongback, a supplemental locking means is provided, as shown in Fig. 3, which comprises a pair of depending detents 44 and 46 spaced on the clip sufliciently to form a locking recess 47 to receive the strongback prior to the clamping action. The strongback is aligned with recess 47 by detent 44 which extends into the path of lip 26 as it is slid under the clips, the purpose being to function as a stop to prevent further rotation of the strongback. Lip 26 may be cammed into engagement with clip 24 over detent 46 by sloping the horizontal leg 48 of clip 24. If desired, the free edge of clip 24 may be offset by slightly canting the clip mounting so that clip 24 is wedged to the vertical lip wall 50 in the clasped position.

To expedite the application to cover 16 and insure proper positioning with respect to strongback 20, some alignment means is desirable that will aiford an axial movement between the members and, also, in the case of the rotatable strongback illustrated, a turning movement. One means for accomplishing this result is the combination of a pin 52 and a thimble 54 and, to facilitate assembly of the strongback, thimble 54 is centrally anchored to cover 16 and pin 52 fixed to strongback 20. Pin 52 fits freely in thimble 54 to permit the strongback to be turned and lifted independently of the cover.

Disassembly of cover 16 from the secured position in Fig. 2 is effected by lifting lever 36 to the broken line position which releases the clamping force applied by cams 32 and permits removal of strongback lip 26 from clip recesses 47. While handle 38 is still gripped by the operator, strongback 20 may be rotated counter-clockwise to unclasp lips 26 and clips 24. Thereafter to gain access to opening 12 cover 16 may be removed as a unit or separately. To seal the opening, cover 16 is positioned cover the opening with gasket 28 in contact with rim 18. strongback 20 being suspended by lever 36 is properly aligned over the cover by engaging pin 52 and thimble 54, and the strongback may be simultaneously rotated to a clasped position where the lips abut detents 44 and the strongback is aligned with recess 47. With the cover thus properly set, handle 38 is fully depressed to rotate cams 32 and, as the strongback is rigid, the cams urge the cover into sealing engagement throughout the perimeter of rim 18 to lock the strongback in recess 47 to prevent accidental separation. Thus the cover may be applied and locked in sealing engagement in one continuous movement requiring only'one hand of the operator.

The foregoing invention oifers a cover assembly that is simple and inexpensive in construction, the component parts of the assembly being readily stamped of sheet metal. The need for tools or assistantance of helpers is avoided since the cover can be quickly applied and locked by continuous movement and with a minimum of effort. Also, supplemental locking means may be provided to prevent accidental separation without affecting the quick acting features of the cover, so that, as now can be appreciated, the invention provides a cover that aifords the sealing efliciency of the prior plural cam-locks while, at the same time, substantially eliminates the operative dilfisultics inherent in the plural arrangements of these earlier locks.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims theinvention may' be practiced otherwise than as specifically described.

I claim:

1. A cover assembly for sealing a wall opening comprising a rim member projecting upwardly from the perimeter of said opening, a resilient cover member provided with a radially-extending circumferential and downwardly facing U-shaped flange adapted to fit over said rim, a gasket disposed in said U-shaped flange for ccntrally engaging the free end of said upwardly projecting rim member, a pair of clips disposed radially outwardly and diametrically of said rim member, an independently rotatable locking bar provided at its ends with depending hooks adapted to be rotatably engaged beneath said diametri-c pair of clips, a downwardly-projecting pin centrally carried by said bar and freely slidable in a bearing in said cover for axially aligning the cover and the bar and for permitting rotation of said bar independently of said cover, and a cam pivotally mounted on said bar and movable against said cover for exerting an upward force on the bar capable of securely interlocking said hook and clip engagement and a downward force on said cover capable of clamping together the rim and the cover and of pressing said free end of the rim into said gasket whereby said gasket is sealably compressed, said cam being shaped to exert said forces in an over-center pivoted position maintainable through force exerted by said resilient cover.

2. A cover assembly according to claim 1 in which said clips each are provided with a pair of downwardlyextending detents for retaining said bar in said locked position, one of the detents being longer than the other for limiting the rotation of said hooks beneath the clips.

References Cited in the file of this patent UNITED STATES PATENTS 707,011 Reynolds Aug. 12, 1902 984,005 Joy Feb. 14, 1911 1,260,299 Banes Mar. 26, 1918 FOREIGN PATENTS 513,355 France Oct. 30, 1920 577,890 France June 16, 1924 682,765 France Feb. 18, 1930 

